Slider

I have a question that I ask for the percentage of a few items, and they should sum up for 100%. I used the slider type of question, and gave each item a line with a slider. my problem is that each line can reach 100%, so suming up won't be 100% - It can be lower or higher. Do I have an option to limit the answers so it will be 100% for all items together? Also - how do I limit an answer so it will be only numeric for example I want to know the age and I want the answer to be numeric (20) and not with words (twenty).